An optical lens such as a spectacle lens manufactured in a factory is wrapped in a comparatively soft material called an inner sheet so the optical surface (lens surface) will not be damaged, put in a lens bag, and shipped.
An optical lens base during the manufacture is kept or conveyed as it is stored in an exclusive tray or washing rack. In this case, usually, the surface of the optical lens base is protected with a protective film so the surface of the optical lens base will not be damaged or dust will not attach to it (Japanese Patent Laid-Open No. 6-347611).
When the optical lens base is to be formed to have a predetermined outer shape by edging or the lens surface is to be polished, if the optical lens base is blocked directly, the lens surface may be damaged. For this reason, usually, the optical lens base is blocked through a protective film (Japanese Patent Laid-Open Nos. 2003-053646 and 7-156052, Japanese Utility Model Laid-Open No. 6-024852, and Japanese Patent Laid-Open No. 9-225798).
The term “optical lens base” in the present invention is employed as a generic term that refers to the following products as a whole:
(1) a spectacle optical lens (a glass lens, plastic lens, or semifinished lens) and its intermediate product;
(2) an optical lens (a lens or an optical filter) in a camera, telescope, microscope, or the like, and its intermediate product; and
(3) a lens mold for a lens forming mold
In the lenses with a protective material described in Japanese Patent Laid-Open No. 6-347611, a transparent strippable sheet is brought into tight contact with each lens surface of an optical lens. As the sheet, a commercially available antistatic sheet, e.g., one called a strippable sheet manufactured by SIMON, COBURN, Hitachi Gousei Kagaku or the like, Raffrezu (Tradename) manufactured by Tonen Sekiyu Kagaku, or Hibron film (Tradename) manufactured by Mitsui Toatsu Sekiyu Kagaku is used by cutting into an appropriate size.
The lens holder described in Japanese Patent Laid-Open No. 2003-053646 serves, when forming an unprocessed circular lens into a pin face lens by edging and beveling, to hold the convex-side lens surface of the lens through a thin double-adhesion elastic seal.
According to the optical lens base polishing method described in Japanese Patent Laid-Open No. 7-156052, the convex-side lens surface of an optical lens base is held by a mounting pan for polishing through a protective film layer and a low-melting metal, and the concave-side lens surface of the optical lens base is polished by the polishing pan. The protective film layer has water solubility and adhesion properties with respect to a low-melting alloy, so it can be removed by washing with water.
The lens holder described in each of Japanese Utility Model Laid-Open No. 6-024852 and Japanese Patent Laid-Open No. 9-225798 is used when edging and beveling a spectacle lens. In the same manner as the lens holder described in Japanese Patent Laid-Open No. 2003-053646, this lens holder forms a cylinder and has a concave spherical lens holding surface at its distal end face. The convex-side lens surface of an unprocessed circular lens is held through a thin double-adhesion elastic seal adhered on the holding surface.
A lens forming mold used in molding an optical lens, e.g., a plastic lens forming mold, comprises a pair of lens molds (to be also referred to as molds hereinafter) made of glass, and a cylindrical gasket (“Spectacles” Published by Medical Aoi Shuppan, May 22, 1985, pp. 83 to 85, and Japanese Patent Publication No. 58-45940). The pair of molds are fitted in the gasket such that their transfer surfaces oppose each other. The space surrounded by the gasket and the pair of molds forms a cavity. A monomer is injected into the cavity and heated for polymerization in an electric furnace to form a plastic lens. Usually, the pair of molds are kept as they are stored in an exclusive washing rack with their transfer surfaces being protected with protective films.
In this manner, when manufacturing an optical lens such as a spectacle lens, to obtain a nondefective lens surface, in the respective manufacturing steps, a protective film is adhered to the lens surface of an optical lens or its intermediate product, or to the transfer surface of a mold so as to protect the lens surface or transfer surface. Thus, the lens surface or transfer surface will not be damaged, or a foreign substance will not attach to it. The optical lens or its intermediate product, or the mold is damaged mainly as it directly comes into contact when storing it in the washing rack or extracting it from the rack, or may also be damaged indirectly by a foreign substance or the like attaching to its surface. Attaching of the foreign substance poses an issue because the foreign substance is difficult to discriminate in appearance from a damage in an inspecting step. Hence, the optical lens, its intermediate product, or the mold is stored in the washing rack as it is protected by the protective film, and conveyed and kept. The protective film is removed when the optical lens, its intermediate product, or the mold is extracted from the washing rack and processed or used. The optical lens, its intermediate product, or the mold is washed after the protective film is removed, to get rid of the foreign substance or contamination attaching to its surface.